I guess it depends upon the amount of curry sauce you are making for how much of a main ingredient, how hungry those four people are expected to be. I am old fashioned and always cook extra. I don't like going short. Leftovers can be eaten next day.
The amount I have given is for 4 kg of chicken. So if you are cooking 1 kg. I guess you will add one fourth.
The quality of spices and their potency varies. I always recommend that you taste your spice/masala/curry mix or sauce, before adding chicken and also after your dish is cooked.
These masalas are only a rough guide. You must always taste your curry before finishing and adjust according to your taste.